A c-driver client can't currently access the collections "files" and "chunks" in the mongoc_gridfs_t. Accessing these is important in case a client wants to refine the semantics of files deletions (example e.g. in the nsfmongo driver ("git clone git://alice.wu-wien.ac.at/nsf" see nsf/library/mongodb/nsfmongo.c, code around MONGO_HAS_NO_GRIDFS_COLLECTION_ACCESSOR). Providing an accessor just for reading access should be quite harmless. Without the patch, a client has to include the private header files.

Attached is a patch relative to the current head version of the mongo-c-driver.